The evaluation of short- and long-term stability studies for brimonidine in aqueous humor by DPV/BDDE method-possible application for direct assay in native samples was written by Radulovic, Valentina;Aleksic, Mara;Kapetanovic, Vera;Rajic, Katarina Karljikovic;Jovanovic, Milos;Marjanovic, Ivan;Stojkovic, Milenko;Agbaba, Danica. And the article was included in Analytical and Bioanalytical Chemistry in 2019.Related Products of 70359-46-5 This article mentions the following:
A novel voltammetric method was developed for brimonidine (BRIM) determination in deproteinized aqueous humor, simplifying preparation of biol. samples for anal. for stability studies. The differential pulse voltammetric (DPV) method using boron doped diamond electrode (BDDE), based on characteristic oxidation peaks, is proposed and successfully applied. The linearity range was within 5.0 × 10-6 to 5.0 × 10-5 M of brimonidine, and limit of detection and limit of quantitation were 1.94 × 10-6 M and 6.46 × 10-6 M, resp. Intra-day and inter-day precision and accuracy were evaluated and all results were in accordance with validation ICH guidelines. The best short-term stability study results were obtained for a concentration level of 3.0 × 10-5 M expressed by deviation of + 1.86% between initial and post storage concentrations A long-term stability study was performed for two concentrations of 3.0 × 10-5 M and 5.0 × 10-5 M and resulted in deviations of + 1.63% and + 3.56%, resp. A freeze and thaw stability study indicated that samples might be frozen only once. The enhancement of DPV/BDDE method sensitivity gained by modification, for the anal. of immeasurable BRIM quantities in native, untreated aqueous humor, was reached for quantities of 6 or 12 nmol/0.1 mL aqueous humor with acceptable accuracy (up to + 7.5%). The nature of the process-the irreversible one electron oxidation voltammetric peak of BRIM-limited the sensitivity. Only electrochem. pre-treatment of the BDD electrode before each measurement significantly speeded up the whole procedure. The advantages of the proposed method are simplicity, short-time performance, and good specificity/selectivity, as well as satisfactory accuracy, and no chem. modification of BDDE was necessary. In the experiment, the researchers used many compounds, for example, 5-Bromo-N-(4,5-dihydro-1H-imidazol-2-yl)quinoxalin-6-amine (2R,3R)-2,3-dihydroxysuccinate (cas: 70359-46-5Related Products of 70359-46-5).
5-Bromo-N-(4,5-dihydro-1H-imidazol-2-yl)quinoxalin-6-amine (2R,3R)-2,3-dihydroxysuccinate (cas: 70359-46-5) belongs to quinoxaline derivatives. Quinoxaline derivatives are important constituents of pharmacologically active compounds, including antibacterial, antibiotic and antineoplastic, antifungal, anti-inflammatory and analgesic drugs. Quinoxalines are used as dyes, pharmaceuticals, and antibiotics such as echinomycin, levomycin exhibiting antitumoral properties. Quinoxalines establish also the basis of anthelmintics and receptor antagonists.Related Products of 70359-46-5
Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider